1. Field of the Invention
The present invention relates to a portable USB (universal serial bus) devices and, more particularly, to such a portable USB device built with a rechargeable functional apparatus.
2. Description of Related Art
Over the past several decades there has been a considerable growth in electronics. The trend of electronic products is compact, portable, low power, and/or multifunctional in order to bring a great convenience to vast consumers. The electronic products comprise, for example, USB card reader, USB wireless device, and portable USB hard disk, and all of which are portable. In using these electronic devices, the user simply inserts the portable USB hard disk in an USB socket of a personal computer, notebook computer, PDA (personal digital assistant) or digital camera for reading data therefrom, writing data into the portable USB hard disk, or for wireless transmission. Typically, the portable USB hard disk has a size about a thumb with a storage capacity of up to hundreds of MB. Typically, the memory of the portable USB hard disk is implemented as a flash memory. In the case that a USB connector of the portable USB hard disk is coupled to the USB socket of the associated device, power may be fed from the device to the portable USB hard disk via a power pin (+5V) of the USB connector for maintaining a normal operation of the flash memory. Furthermore, data stored in the flash memory can be accessed via data pins (D+ and D−) of the USB connector. In other words, the flash memory operates as a hard disk of a conventional computer.
As stated above, the USB hard disk has advantages of portability, compactness, being easy to use as a hard disk. Thus, continuing improvements in the portable USB hard disk are constantly being sought.